Send gateway commands after DB transaction is commited

There are several places where a gateway command (ACL update etc.) is sent within a pending DB transaction.
This means that if a transaction is rolled back, the gateway state will no longer reflect what is actually stored in the database.

We should consider making it consistent and always sending events after a successful commit.

Some affected functions:
- `sync_all_networks`
- `sync_allowed_user_devices`
- `delete_user_and_cleanup_devices`

Start by locating sync_all_networks, sync_allowed_user_devices, and delete_user_and_cleanup_devices, then inspect their database transaction boundaries and gateway command calls. Verify that gateway commands are sent only after a successful commit, with no command sent when the transaction rolls back.

Written by the indexing model from the issue text.